It is well known that a projected image may be enhanced with an appearance of depth by converting the projected image into a so-called 3D image. This is most often accomplished by optically polarizing the images which are to be viewed by a viewer's left eye differently than the images which are to be viewed by a viewer's right eye. The 3D effect is perceived by the viewer when the viewer views the polarized images though the use of polarized filter lenses, commonly configured as ‘3D viewing glasses’ with a polarized filter for use with the left eye of the viewer and a differently polarized filter for use with the right eye of the viewer. When the 3D viewing glasses are used to view the 3D images, the left eye of the viewer sees only the light polarized appropriately for passage through the polarized filter associated with the left eye and the right eye of the viewer sees only the light polarized appropriately for passage through the polarized filter associated with the right eye of the viewer. The above described method of displaying 3D images is known as passive 3D viewing where the projector alternates the left eye information with the right eye information at double the typical frame rate and a screen/filter/polarizing blocker in front of the projector's lenses alternates the polarization of the projected image in such a way that the image of each eye passes through the corresponding polarizing filter of the pair of passive stereo glasses discussed above. An alternative to passive 3D viewing is active 3D viewing where each viewer wears glasses with LCD light shutters which work in synchronization with the projector so that when the projector displays the left eye image, the right eye shutter of the active stereo eyewear is closed, and vice versa. A problem with the above described methods of projecting a 3D image is that the viewer does not perceive the side depth view when the viewer moves his head around with respect to the projected image.
Another known method of producing a 3D image is through the use of multiple projectors, where each projector is typically located at different locations and is focused onto the same screen. In this configuration, each pixel of the display is able to emit light beams of varying color, intensity and direction, so that a viewer viewing a pixel from a first point of view will perceive a different output from that pixel than a person viewing the same pixel from a second point of view. While the system above is able to create a 3D image viewable in substantially full depth from a variety of view points, a system which requires multiple projectors to accomplish 3D image projection can be very costly and may have difficult issues with proper alignment and/or calibration between the multiple projectors.
Another known method of producing a 3D image is through the use of a pinhole array which typically incorporate a screen having pinholes through which projected light may pass. Each pinhole then appears as a point light source, displaying varying intensity and direction therefrom and the image being perceived as having depth when viewed from a prescribed position. However, pinhole array systems are known for having a single best viewer location. In other words, as the viewer moves about with respect to the pinhole array, the depth and intensity of the 3D image are degraded based upon even slight variations in location.
While there are many advanced methods of displaying 3D images, much room for improvement remains. It is therefore desirable to develop a lower cost 3D image projection system with the ability to view the projected 3D image from various view points.